Mark Levinson - how to fix white logo paint that has peeled away?

Even if you found the right white, the paint on the amp would probably discolored after all of these years. It would likely be unnoticeable though. Just put the thin paint in the trough carefully with a pin as another said. 

If it is a water based paint you could also quickly wipe off any that strayed outside of the trough.

Or, and I know this is going to sound weird, but find a guy who collects and paints miniature soldiers. I have a friend who does this and what he can do with a paint brush is unbelievable.

I'm impressed with all the replies, thank you guys.
I called Levinson, they don't manufacture a new face plate anymore, I considered that a solution.
The miniature soldier suggestion was pretty good, ha ha. 

The microdabber suggestion was the best one. If I spread the new paint to blend with the original, then whatever minor shade difference would blend in.
I feel like if I try to re-paint it, it will never look right.  I showed the pre to several people and not a single one noticed the missing part of the logo. They just had a mental map of how it should look and it seemed perfect.
Anyway thanks all.